Novel coronavirus nucleic acid testing is a key technical support for effective prevention and control of new coronavirus outbreaks. So, what is the principle of the novel coronavirus nucleic acid test?

Novel coronavirus nucleic acid testing is essential for early clinical detection, diagnosis, isolation and treatment, and is a key technical support for effective prevention and control of the new coronavirus pneumonia epidemic.

What is the principle of the new coronavirus nucleic acid test?

Viruses are characterized by a very small form that cannot be seen under an ordinary light microscope and cannot be directly observed by the naked eye. However, each virus has its own unique genetic sequence, and the presence of a virus in a patient's body can be determined by detecting the viral nucleic acid in the patient's body.

Nowadays, most of the virus nucleic acid test kits use fluorescent quantitative PCR method. The detection principle is to use the unique gene sequence of the virus as the detection target, through PCR amplification, so that we choose this target DNA sequence exponential increase, each amplified DNA sequence, can be combined with a piece of our pre-added fluorescent labeling probe, generating a fluorescent signal, the more target genes amplified, the stronger the accumulated fluorescent signal. The more target genes amplified, the stronger the accumulated fluorescence signal. In samples without virus, there is no target gene amplification, so no fluorescence signal enhancement is detected. Therefore, nucleic acid detection, in fact, is to determine the presence of viral nucleic acid in the sample by detecting the accumulation of fluorescence signal.

Factors affecting the accuracy of nucleic acid testing

The accuracy of nucleic acid test results is not only related to the accuracy of the test kit itself, but also closely related to the timing of the test sample collection and the type of test sample. First of all, the timing of sampling is important. If the patient has just eaten or brushed his teeth, and the virus in the pharynx has been washed away, and the collection is done at this time, the nucleic acid test will easily show negative results even in patients who are positive for viral infection. Therefore, experienced health care professionals usually ask patients not to drink or eat before collecting respiratory samples.